It is known that a blend of diene polymer rubber in which the rubber may be in major proportion and polyethylene can be vulcanized to give thermoset vulcanizates by conventional curing techniques. Gessler, who was one of the first to investigate dynamic curing, suggested that thermoplastic vulcanizates, useful whenever a high tensile strength semi-rigid plastic was required, could be prepared by the dynamic curing of a blend of 5-50 parts rubber and 95-50 parts polypropylene with curing agents which do not contain peroxide (Gessler -- U.S. Pat. No. 3,037,954). However, the process was not demonstrated with highly unsaturated rubber, i.e., diene rubbers of high functionality. More recently, thermoplastic products have been prepared from blends of diene rubber of low functionality and polyolefin plastics in which the proportions could vary widely providing that the extent of cure was carefully controlled so as to effect only a partial cure (Fischer -- U.S. Pat. Nos. 3,758,643 and 3,806,558). It is, of course, well known that diene rubbers of high functionality have a strong propensity to react with curatives to form thermoset products. In any event, the preparation of flexible thermoplastic tough elastic products comprising blends of diene rubbers of high functionality and polyolefin resins has not heretofore been accomplished.